Four studies that spanned over two decades were used in the report, which concludes that current advice to not place infants on their stomach or side to sleep especially applies when those babies are swaddled.

The risk of SIDS doubled or nearly doubled when swaddled babies were on their sides or stomachs to sleep.

The risks were also higher for older infants who were swaddled during sleep because those babies presumably moved onto their stomachs or sides after being placed on their backs.

Back is best and the American Academy of Pediatrics recommends that healthy infants be put to sleep on their backs.